Sokwe wrote:The classical way to solve this is with Buckingham's B->r, giving a new R421 conduit...

Funny, I thought I had figured out that that didn't work for some reason. It certainly looks good now!

A strange and useless coincidence: there's a known R421 with a different output Herschel location. This might be the first case where the output orientation and timing isn't sufficient to identify a Herschel conduit:

Sokwe wrote:Unfortunately, it might not be very useful due to its size and high repeat time.

One of the old standard ways of proving usefulness was to use the conduit successfully in a period-N gun from Jason Summers' gun collection. In point of fact, the new R421 is quite useful for building compact guns, especially higher-period guns, because the Herschel travels unusually slowly. Here's the old p485 gun, for example:

The same is true for the p970, of course. This actually might turn out to be a moderately useful delay conduit; it's quite hard to fit a delay of 400+ ticks into that small a space. Herschels travel much faster than this on average, and therefore take up more space.

That means the R421 can potentially reduce quite a few existing higher-period guns that rely on length-N or length-2N or length-3N Herschel loops. (There are a lot of these -- in particular, most of the prime-period guns are Herschel loops, for obvious reasons.)

EDIT: The safe repeat rate for the conduit is 363 ticks, by the way. It would be much smaller if it weren't for the extra output glider that crosses the next Herschel's path rather late in the reaction. There seems to be definitely not enough room to catch that glider with a 7x9 eater, a boat-bit catch, or any other tricks I can think of, so I guess we'll just have to live with the high recovery time. There are a few lower periods like p300 where the glider is naturally suppressed by the following Herschel.

Extrementhusiast wrote:This seems like a very promising starting point for a different stable reflector...It can use a block, boat or beehive at that location. (This may also be somewhat promising for a Herschel conduit.)

Huh, I don't remember running into that one before. Set up for a catgl run, it looks like this:

But now we're primarily looking for the rare cases where a block, boat, or beehive shows up again at the right location. Catalysts can be placed anywhere between about T=5 and T=170, and really the second catalyst could be later than that.

First generation to place catalyst: 5Last generation to place catalyst: 139Number of generations for catalyst to survive: 60Total number of catalysts to place; 3Number of parallel processes to run: 1

No luck, unfortunately -- see attached. Here's the one-off script I used to hunt for a lucky leftover piece of stable junk. There weren't any stabilizations that included the two key ON cells common to the block/boat/beehive:

This doesn't prove anything about four or more catalysts, of course, or other catalysts not currently supported by Catgl 1.0.3. It might also be worth trying a ptbsearch search, which could include a transparent catalyst or two in the mix.

But where a two-catalyst search took just a few minutes, the three-catalyst search takes a few hours on my system. Looks like it will require the usual indeterminate amount of work -- hours, days, months, or never -- to get some junk to settle into the right place.

And even if some junk does settle, of course, there's no guarantee there will be an output glider or Herschel, or a lack of other uncleanable junk in the final stabilization. Finding this kind of thing efficiently will take a better search and filtering system.

On the other hand, you never know. Someone could adjust the input pattern to include a likely first catalyst, and run a new 3-catalyst search. That would be an almost completely new search space every time, and post-test.py might pop up a perfect G-to-H or G-to-G any time.

-- Probably won't, though. This looks like the kind of problem that needs a combination of unreasonable dedication and a lot of beginner's luck...!

@dvgrn Did you tried to add some more catalysts found with bellman? Maybe we can stay on 3 catalysts but if we'll have more options it would be something in-between the regular 3 and 4 catalysts.

EDIT Congrats on the new conduit and the improved guns (will add them soon into the gun list).

Obviously time delay mechanisms have their own use - so although usually we would like to have fast small conduits sometimes it's definitely useful to have slow and compact conduits, obviously as more time delay we want, the more complex it is to reach it in compact space.

dvgrn wrote:But now we're primarily looking for the rare cases where a block, boat, or beehive shows up again at the right location.

Isn't it sufficient if there exists a glider that can be collided with the resulting junk to make a pi in the right location? I don't think that's any more likely, but who knows?

True enough. A really thorough test of the output would maybe send in a fresh glider on each possible lane, and see if a pi showed up and all leftover junk conveniently disappeared.

It would have taken longer to write that test, though, and a lot longer to run it, because the pi could show up any time, not just at T=7. It seems as if a pi from a nonstandard reaction might show up for every thousand regular block/boat/beehive solutions, so the more thorough test wouldn't increase the success rate very much.

I'm wildly guessing about this, but if I'm right, then it will be enormously more effective to pick a good first catalyst from the results so far, run a new search with three additional catalysts, and filter again with the imperfect fast test. This is one of those cases where it's impossible to ever look through the entire search space, so you might as well look as quickly as you can at as many different possibilities as you can -- the most likely possibilities first.

There are almost always going to be just-barely-possible reactions that we're going to miss in this kind of automated search. In particular, even a good search result is very likely to need some manual cleaning up. The preliminary R421 conduit that catgl actually found also produced an extra block. I manually placed an eater to clean it up. If I'd been trusting even a slow thorough automated test to find the good results for me, this reaction would have been disqualified because of the block.

It would take a really smart filter to say, "this block is near the edge of the reaction envelope, so it's worth checking to see if it can be removed, and this other thing is an R-pentomino so we should try to tame it with known R-to-B conduits." It's hard to write an algorithmic substitute for this kind of human pattern recognition.

Brice Due started writing a new ptbsearch/catalyst search utility back in 2006, that scanned each generation of each reaction to find Herschels, B's, R's, and maybe optionally *WSSes and switch engines and other small interesting active objects. An early version, using only eaters as catalysts, found the F171 conduit. Unfortunately the program never got past the stage of editing the source code to change the search -- a sadly common fate for Life search utilities.

I believe Paul Chapman has some working code along the same lines, that he ran for some months off and on a few years ago, to look for a Spartan Snark.

Running a Herschel + early eater combo through Bellman comes up with simple, but not obvious, catalysts. Some unusual applications of tubs, too. The search looks like it's ending soon, but maybe something else will come up.

Kazyan wrote:Running a Herschel + early eater combo through Bellman comes up with simple, but not obvious, catalysts. Some unusual applications of tubs, too.

Nice! The one in the upper left corner looks interesting. There's a natural Herschel signature coming out, with the B-heptomino block already cleaned up, and only a few extraneous pieces of junk to suppress. Unfortunately it looks like it may not be possible to protect the early eater from early destruction, without also losing the Herschel output.

If someone plans to try running catgl or ptbsearch on any of these, or Kazyan's previous Bellman catalysts, it might make sense to post a claim so that other people don't waste time on the same search. I've started a thread for new Herschel conduit searches so that we don't clutter up this Bellman thread any more.

Just by the way, this seems like the kind of pattern that LifeHistory state 6 was invented for. It's nice to be able to run a subpattern to completion without having to worry whether part of the reaction is really an intruding glider from another part of the stamp collection:

I've put together a matrix of the mostly-Bellman-related Herschel results posted so far, so that we can refer to the various catalysts without quoting them all the time. The first two rows, A and B, are from Kazyan's first posting. C is Extrementhusiast's contribution, and D is Kazyan's Herschel-plus-early-eater search.

Jackk wrote:Probably useless but I had to post it: Pi to clean Queen Bee -

A use was found for that reaction once upon a time, though maybe not a very useful use.

It turns out that a simple eater will do the same thing as that table-snake-bookend catalyst in this case, and that that it's possible to build a Herschel splitter with it, with the addition of a pentadecathlon:

Has anyone investigated whether a Bellman-generated P1 catalyst can shove that beehive back into position? There's not a whole lot of room there on the axis, but there's a lot more than the pentadecathlon needs.

Also I seem to recall there might be a few more workable R-to-Herschel conduits available these days, that could also be used after the split.

But P15N is very limiting. If you're not careful, you start wondering why you're using huge awkward Herschel circuitry at all, instead of P30 guns and reflectors and so on. So it's probably not worth investigating unless a good substitute can be found for that oscillator.

I haven't been very active in exploration of Life but I was recently fascinated by the 3c/10 pi movement and did a little research on this topic. I wasn't able to find any reported stable pi channel which rather surprised me, but then I didn't even come across the pi turning reaction posted at viewtopic.php?p=20067#p20067 which isn't in the elementary conduits collection.I also found it very difficult to search for pi specific patterns on conwaylife.com because of the three character minimum for search terms, but this google search does turn up a bunch of interesting related results (along with some less relevant results: https://www.google.com.au/search?q=site ... +converter

If a catalyst (most likely found with Bellman) could restore the beehive, this would result in a "one-fifth snark". I've tried using Bellman to find one, but with no success, mostly to do with my lack of experience with the search program. Would anyone else more experienced like to have a go?...